To mitigate the global greenhouse gases (GHGs) emissions, carbon dioxide (CO2) capture and storage (CCS) has the potential to play a significant role for reaching mitigation target. Oxy-fuel combustion is a promising technology for CO2 capture in power plants. Advantages compared to CCS with the conventional combustion technology are: high combustion efficiency, flue gas volume reduction, low fuel consumption, near zero CO2 emission, and less nitrogen oxides (NOx) formation can be reached simultaneously by using the oxy-fuel combustion technology. However, knowledge gaps relating to large scale coal based and natural gas based power plants with CO2 capture still exist, such as combustors and boilers operating at higher temperatures and design of CO2 turbines and compressors. To apply the oxy-fuel combustion technology on power plants, much work is focused on the fundamental and feasibility study regarding combustion characterization, process and system analysis, and economic evaluation etc. Further studies from system perspective point of view are highlighted, such as the impact of operating conditions on system performance and on advanced cycle integrated with oxy-fuel combustion for CO2 capture. In this thesis, the characterization for flue gas recycle (FGR) was theoretically derived based on mass balance of combustion reactions, and system modeling was conducted by using a process simulator, Aspen Plus. Important parameters such as FGR rate and ratio, flue gas composition, and electrical efficiency etc. were analyzed and discussed based on different operational conditions. An advanced evaporative gas turbine (EvGT) cycle with oxy-fuel combustion for CO2 capture was also studied. Based on economic indicators such as specific investment cost (SIC), cost of electricity (COE), and cost of CO2avoidance (COA), economic performance was evaluated and compared among various system configurations. The system configurations include an EvGT cycle power plant without CO2 capture, an EvGT cycle power plant with chemical absorption for CO2 capture, and a combined cycle power plant. The study shows that FGR ratio is of importance, which has impact not only on heat transfer but also on mass transfer in the oxy-coal combustion process. Significant reduction in the amount of flue gas can be achieved due to the flue gas recycling, particularly for the system with more prior upstream recycle options. Although the recycle options have almost no effect on FGR ratio, flue gas flow rate, and system electrical efficiency, FGR options have significant effects on flue gas compositions, especially the concentrations of CO2 and H2O, and heat exchanger duties. In addition, oxygen purity and water/gas ratio, respectively, have an optimum value for an EvGT cycle power plant with oxy-fuel combustion. Oxygen purity of 97 mol% and water/gas ratio of 0.133 can be considered as the optimum values for the studied system. For optional operating conditions of flue gas recycling, the exhaust gas recycled after condensing (dry recycle) results in about 5 percentage points higher electrical efficiency and about 45 % more cooling water consumption comparing with the exhaust gas recycled before condensing (wet recycle). The direct costs of EvGT cycle with oxy-fuel combustion are a little higher than the direct costs of EvGT cycle with chemical absorption. However, as plant size is larger than 60 MW, even though the EvGT cycle with oxy-fuel combustion has a higher COE than the EvGT cycle with chemical absorption, the EvGT cycle with oxy-fuel combustion has a lower COA. Further, compared with others studies of natural gas combined cycle (NGCC), the EvGT system has a lower COE and COA than the NGCC system no matter which CO2 capture technology is integrated. / QC 20111123

Global carbon emissions are higher than ever before and in the last decade of 21st century, focus has shifted on reducing these emissions in various ways possible. Carbon capture, utilization and storage (CCUS) has been identified as one of the important ways to reduce carbon emissions and meet climate targets. For a long time, Sweden has promoted the use of biomass as fuel for heat and power generation which has enabled it to meet its climate targets earlier than projected. Now, major Swedish energy companies are looking into coupling exiting biomass fired heat and power plants with CCUS. This opens up the possibility of attaining negative emissions, also known as Bio Energy Carbon Capture and Storage (BECCS). With the right policy framework in place, BECCS can be a major boon and help Sweden attaining net zero carbon emissions. As a contribution in meeting net zero targets, this thesis is aimed to evaluate the installation of a carbon capture plant to abate flue gas emissions from District heating facility in Jordbro which is a ~70 MW (fuel) CHP plant running on biomass.  Among the available carbon capture technologies, Calcium oxide-based carbon capture has been expected to show great promise due to its lower environmental impacts and possibility to extract high quality energy when installed. Hence a concept system for integration calcium looping at Jordbro has been developed through the use of modeling tools like ASPEN. A techno economic assessment was needed to be performed to give conclusive results on the overall viability of the process. Further, key process indicators like energy penalty, plant footprint and cost of capture per tonne of CO2 were identified for making the final evaluation. Finally, through a strategic collaboration with SaltX, major process improvements were introduced and applied to the modeled process.  It was concluded that with the current average flowrates at Jordbro it was possible to capture 154,000 tonnes of CO2 annually. The required amount of energy input to the calciner is 48MW (7.29 MW/kg-CO2 captured) which is one of the major findings of this study. Even though a significant amount of heat is recovered, the main boiler is not capable of producing heat over 900 οC and additional biomass needs to be combusted, leading to an additional CO2 emission of about 125 000 tonnes annually. Considering an optimal integration, the energy penalties became 6.25 %.  However, the plant footprint increased substantially due to requirement for burning additional biomass in the regeneration reactor and addition of several auxiliary units that come along with calcium-based carbon capture. Further, the total capital investment for this project is 1,219 MSEK with reactor costs being most capital intensive. Assuming a plant life of 25 years, the cost of capture per tonne of CO2 (excluding the costs for carbon transport and storage) was evaluated at 988 SEK, which is 58% higher than the reference Mono-ethanol amine based chemical absorption case. The innovative improvements from SaltX substantially reduced the plant footprint but capture costs did not reduce since material transport costs proved to be the major bottleneck.  Upon comparison of this technology with the amine-based technology it was found that Calcium oxide-based carbon capture would need further research and improvements to be more viable than amine-based carbon capture. Integration of thermal energy storage and process intensification can be the possible paths for further improvement.

High and medium-voltage digital substations play an essential role in the energy transition since they are part of the equipment required to deploy smart grids. With the gradual increase of smart grids, energy systems are becoming more flexible with the growing penetration of renewable energies and distributed energy generation. Simultaneously, the energy system’s efficiency increases, with load supply precisely where required and reduced losses. Medium voltage stations have not been upgraded gradually like high voltage stations; therefore, most of Stockholm’s medium voltage stations are considered old and do not include digital remote monitoring or remote-control features. These conventional stations must be retrofitted with digital technology or replaced with new digitized stations. Previous studies show the technical potential of updating non-digitized stations to reduce interruption times. Still, a systematic assessment of these types of projects’ profitability is missing. This project aims to perform a techno-economic assessment for retrofitting conventional urban medium voltage substations with digital technology, modeling different configurations of digitalization (levels 1 and 2) to suggest the most convenient set-up, balancing the technical and economic facets. Furthermore, it investigates the prospect and profitability of reducing interruption times by 50% with the digitization of substations. The methodology proposed used a reference test system based on the most representative type of network for an urban medium voltage network in Stockholm: A Double cable – open loop structure consisting of 5 single cable secondary substations. A calculation method was performed to obtain the expected results evaluating all the possible combinations of digitalized stations in the feeder line. Results suggest that the best outcome is formed by the last station retrofitted with remote control (level 2) and the other four stations with monitoring (level 1). This setup could reduce SAIDI by 71% and the total customer costs by 26.3%. To make this outcome profitable, a reduction in Omexom Labor Costs of 13.6% is required if a discount rate of 7% is used, but if this value is below 4.65%, a reduction in Labor Costs is unnecessary. Furthermore, results show that a set-up of 5 monitoring digitized stations can reduce SAIDI by 56.8%. Thus, it aligns with Ellevio’s objective to reduce by half their interruption times. A reduction of 12.9% in Labor Costs would be required to achieve this as a profitable setup; on the other hand, if the discount rate is below 4.65%, it is unnecessary. / Digitala hög- och medelspänningsstationer spelar en avgörande roll i energiomställningen eftersom de är en del av den utrustning som krävs för att implementera smarta elnät. Med den gradvisa ökningen av smarta elnät blir energisystemen mer flexibla med den ökande penetrationen av förnybar energi och distribuerad energiproduktion. Samtidigt ökar energisystemets effektivitet, med lastförsörjning precis där det behövs och minskade förluster. Medelspänningsstationerna har inte uppgraderats gradvis som högspänningsstationerna; därför anses de flesta av Stockholms medelspänningsstationer vara gamla och inkluderar inte digital fjärrövervakning eller fjärrstyrningsfunktioner. Dessa konventionella stationer måste antingen uppgraderas med digital teknik eller ersättas med nya digitaliserade stationer. Tidigare studier visar den tekniska potentialen att uppdatera icke-digitaliserade stationer för att minska avbrottstiderna, men en systematisk bedömning av lönsamheten för sådana projekt saknas. Detta projekt syftar till att utföra en teknisk-ekonomisk utvärdering för att uppgradera konventionella urbana medelspänningsstationer med digital teknik, genom att modellera olika konfigurationer av digitalisering (nivå 1 och 2) för att föreslå den mest lämpliga uppställningen, där tekniska och ekonomiska aspekter balanseras. Dessutom ska möjligheterna och lönsamheten för att minska avbrottstiderna med 50% genom digitalisering av stationer undersökas. Den föreslagna metoden använder ett referenstestsystem baserat på den mest representativa typen av nätverk för ett urbant medelspänningsnät i Stockholm: en dubbelkabel - öppen slingstruktur bestående av 5 enskilda kabelunderstationer. En beräkningsmetod användes för att få de förväntade resultaten genom att utvärdera alla möjliga kombinationer av digitaliserade stationer i matarledningen. Resultaten antyder att det bästa resultatet uppnås genom att den sista stationen uppgraderas med fjärrstyrning (nivå 2) och de andra fyra stationerna med övervakning (nivå 1). Denna uppställning kan minska SAIDI med 71% och totala kundkostnader med 26.3%. För att göra detta resultat lönsamt krävs en minskning av Omexom arbetskostnader med 13.6% om en diskonteringsränta på 7% används, men om detta värde är under 4.65% behövs ingen minskning av arbetskraftskostnader. Dessutom visar resultaten att en uppställning med 5 övervakningsdigitaliserade stationer kan minska SAIDI med 56.8%. Detta stämmer överens med Ellevios mål att halvera sina avbrottstider. En minskning av arbetskraftskostnader med 12.9% skulle krävas för att uppnå detta som en lönsam uppställning. Å andra sidan, om diskonteringsräntan är under 4.65%, finns det ingen anledning att minska arbetskraftskostnader.

No description available.

According to the “Draft development plan for meeting the current and future electricity demandfor 2023-2032” developed by the Polish Transmission System Operator PSE, the most appropriate solution is to significantly expand the possibilities of energy storage, due to its role as a factor improving the power balancing with the increase of wind farms and photovoltaic (PV) sources. Poland has changed the rules governing the energy industry to encourage energy storage. Few barriers have already been eliminated like double charging of transmission fees, but there is still a big novelty to come and that is the reform of the balancing market. With the introduction of this change many more revenue streams should be available that are already present in other EU countries. The objective of this thesis is to provide a high-level overview of the Polish electricity market, identification of existing legal barriers, assessing the role of battery energy storage systems (BESSs) participating in distinct applications, and evaluating a possible business case considering a foreseeable market evolution. The scope of the study is limited to only one storage option Li-Ion standalone project of 10MW/40MWh at HV Point of Connection. In literature review, there does not seem to be a study on storage in the context of Poland. Hence, identifying the research gaps, an analysis of standalone storage system for grid applications in Poland is performed. In this study the NPV, IRR and PP for different scenarios of available revenue streams is determined to compare current and future business models for techno-economic feasibility for BESS in the context of Poland. Results of the study are as following. In the future scenario under the assumed dispatch strategy and participation in CM, FCR, aFRR availability markets as well as aFRR energy market and wholesale arbitrage, the overall project IRR is around 18% with a payback time of around 5 years. Provided the number of new accessible revenue streams BESS can present a strong business case in Poland.

The Paris Agreement has ambitious targets to limit the global warming below 1.5 °Cin the 21st century. This goal is reflected in the national climate targets, for example, Sweden aims to achieve net zero greenhouse gas emissions by 2045, and thereafter achieve negative emissions. One of the pivotal ways to achieve these goals is by applying the mature bioenergy with carbon capture and storage (BECCS) technology to large-scale industries that emit CO2. Around 6% of the global emissions arise from the pulp and paper industry making them one of the largest localized emitters of biogenic CO2. This makes them suitable for retrofitting BECCS technologies and post-combustion capture (PCC) is one among them. This study presents a techno-economic assessment of an absorption-based PCC unit in SCA Östrand pulp mill. Chemical absorption using MEA and chilled ammonia process (CAP) using NH3 as the solvent are considered in this study. For both the processes, mass and energy balances using Aspen HYSYS were done and validated against published data in literature. Heat integration by applying excess or waste heat from the mill is also considered in this work. CO2 capture from flue gas originating from various emission sources in the mill (recovery boiler, lime kiln and multi-fuel boiler) are considered in different combinations in the analysis. The main key performance indicator (KPI) evaluated in this work is the cost of CO2capture for all the different cases for both the MEA- and chilled NH3-based absorption processes. The minimum cost of CO2 capture for MEA-based absorption process was found to be in the range 37-41 €/tCO2 and for CAP, it was found to be in the range 73-81 €/tCO2. For MEA-based absorption process, the excess low pressure steam from the mill satisfies the steam demand in all the cases, except the one where CO2 is captured from all the three emission sources. For CAP, sufficient excess low pressure steam is present in the mill for all the capture cases due to a lower reboiler duty compared to MEA-based absorption process. An optimal process configuration and capture scenario for the existing design conditions in the mill are derived and justified. A sensitivity analysis was carried out to find the associated bottlenecks from the breakdown of the cost of CO2 capture for each process. The overall BECCS cost is also sensitive to CO2 transport & storage costs. However, it is also clear that incentives for negative emissions will make BECCS an attractive solution for the pulp and paper industry.

The industrial sector not only has a big contribution to global emissions but also a low share of renewable energy for heat demand. Knowing that most of the energy consumption in industry is heat and that half of it is at medium-low temperature (below 400 ºC), it is a great market for the integration of solar thermal technologies. Following the criteria of high heat demand and low-temperature requirements, five promising industrial sectors and their processes have been analysed: food and beverage, paper and pulp, chemical, textile and mining. Steam generation at supply level has been considered one of the most promising systems considering its integration advantages and the potential of direct steam generation plants. The market potential study has been geographically determined performing an MCA; countries all over the world have been assessed considering their heat consumption in the promising sectors and other conditions that enhance the SHIP feasibility such as solar radiation levels, favourable energy policies, previous experience in SHIP plants, ease of doing business, etc. The price of natural gas has been also considered after selecting Europe as a suitable market. The potential heat demand that this technology could cover has been estimated considering limitations as the competitiveness with other renewable heat sources, the expected heat recovery potential for some sectors, the solar fraction of the region and roof space of the factories. The results show that the five countries with bigger potential are Germany, France, Netherlands, Italy, and Spain, while the sectors with the most suitable market are food and beverage, and chemical. A case study has been selected based on the previous conclusions: a Fresnel direct steam generation plant in Sevilla (Spain) characterized thanks to the data provided by the company Solatom. The plant has been modelled using the software TRNSYS, taking special consideration in the Fresnel performance, the dynamic steam drum behaviour and its influence on the start-up time of the plant. The results achieved through the techno-economic analysis show that parameters such as solar radiation, conventional fuel prices and EU ETS prices have a major impact on the economic indicators. A sensitivity analysis shows that locations with radiation levels above 1750 kWh/m2 have positive values for NPV, and above 2250 kWh/m2 the cost of generating solar heating (LCOH) is under European natural gas prices. In addition to this, fuel prices above 50 €/MWh, which are common for SMEs, results in payback periods under 10 years. Future trends depict favourable scenarios as current European policies are causing a rapid growth of the ETS. Therefore, solar heat in industrial processes can be a feasible alternative, or work as a complement, to conventional systems. Its deployment is driven by supportive policies, high radiation levels, costly fuels prices (such as the ones for SMEs) and the necessity of reducing GHG emissions and decrease the independence on fossil energies. / Industrisektorn har inte bara ett stort bidrag till globala utsläpp utan också en låg andel förnybar energi för värmebehov. Att veta att det mesta av energiförbrukningen i industrin är värme och att hälften av den är vid medelhög låg temperatur (under 400ºC), är det en fantastisk marknad för integration av solvärmeteknik. Enligt kriterierna för högt värmebehov och lågtemperaturkrav har fem lovande industrisektorer och deras processer analyserats: mat och dryck, papper och massa, kemikalier, textil och gruvdrift. Ånggenerering på leveransnivå har ansetts vara ett av de mest lovande systemen med tanke på dess integrationsfördelar och potentialen hos direkta ånggenereringsanläggningar. Marknadspotentialstudien har fastställts geografiskt med en MCA; länder över hela världen har bedömts med tanke på deras värmeförbrukning i de lovande sektorerna och andra förhållanden som förbättrar SHIP-genomförbarheten, såsom solstrålningsnivåer, gynnsam energipolitik, tidigare erfarenhet av SHIP-anläggningar, lätt att göra affärer etc. Priset på naturgas har också övervägs efter valet av Europa som en lämplig marknad. Det potentiella värmebehovet som denna teknik kan täcka har uppskattats med tanke på begränsningar som konkurrenskraft med andra förnybara värmekällor, den förväntade värmeåtervinningspotentialen för vissa sektorer, solfraktionen i regionen och fabrikernas takutrymme. Resultaten visar att de fem länderna med större potential är Tyskland, Frankrike, Nederländerna, Italien och Spanien, medan de sektorer som har den mest lämpliga marknaden är mat och dryck samt kemikalier. En fallstudie har valts utifrån de tidigare slutsatserna: en Fresnel-ångproduktionsanläggning i Sevilla (Spanien) som kännetecknas av uppgifterna från företaget. Anläggningen har modellerats med hjälp av programvaran TRNSYS, med särskild hänsyn till Fresnel-prestanda, det dynamiska ångtrummans beteende och dess inflytande på anläggningens starttid. De resultat som uppnåtts genom den tekno-ekonomiska analysen visar att parametrar som solstrålning, konventionella bränslepriser och EU: s ETS-priser har stor inverkan på de ekonomiska indikatorerna. En känslighetsanalys visar att platser med strålningsvärden över 1750 kWh/m2 har positiva värden för NPV och över 2250 kWh/m2 är kostnaden för att generera solvärme (LCOH) under europeiska naturgaspriser. Utöver detta leder bränslepriser över 50 €/MWh, som är vanliga för små och medelstora företag, till återbetalningsperioder under tio år. Framtida trender visar gynnsamma scenarier eftersom europeisk politik orsakar en snabb tillväxt på ETS. Därför kan solvärme i industriella processer vara ett genomförbart alternativ eller fungera som ett komplement till konventionella system. Dess utplacering drivs av stödjande politik, höga strålningsnivåer, dyra bränslepriser (som de för små och medelstora företag) och behovet av att minska växthusgasutsläppen och minska självständigheten för fossila energier.

As climate change continues to increase global temperatures and change precipitation patterns, water systems have come under increased pressure, especially from the agricultural sector. These climate effects on agricultural systems have been found to be much greater for small-scale producers and small-island developing nations. As such, the Dominican Republic, a Caribbean island nation with a deep agricultural culture dominated by small-scale farms is especially vulnerable. As a result, there has been a global call to promote more precise and efficient irrigation practices, such as drip irrigation systems, however, these systems most often require an external energy source. With one of the largest contributors to greenhouse gas being energy production, renewable energy should be used to truly have a sustainable irrigation system. Solar-powered drip irrigation systems (SDIS) have been heavily researched and been found to be technically feasible and economically viable, however, the techno-economically optimal configuration is highly dependent on the context in which they are applied. Therefore, this thesis aims to research and present a techno-economically optimal design methodology for SDISs for small-scale Dominican farms. To do so, firstly an in-depth literature review and market analysis were conducted where it was found that a fixed PV array coupled with an AC-powered, variable speed pump should be used. Additionally, the exact pump should be chosen from those locally available that best match the drip irrigation system head and flow rate characteristics. However, the literature pointed to no clear conclusion regarding if and what type of energy storage is best for SDIS. Thus, using the case study of a 1, 2, and 3 ha plot of plantains at Centro de Biotecnología Vegetal (CEBIVE) located on the outskirts of Santo Domingo, the minimum-sized feasible configuration options for a direct-driven SDIS (no storage) along with a battery bank and an elevated water tank were found. These configurations were sized using developed algorithms in Python that used hourly historical weather data from 2010 through 2023 and compared according to their respective net present costs (NPC) over 25 years and initial investment costs. Overall, it was found that for a 2 and 3-ha farm plot size, a direct-driven system was techno-economically optimal. Meanwhile, for a 1 ha farm plot, although the direct-driven system minimizes the SDIS systems NPC, the initial investment cost was found to be minimal for one of the feasible battery configurations (2 350W PV panels plus 1 kWh of lithium-ion battery capacity). In this case, the NPC of the battery configuration was 36.8% more than the direct-drive system, however the initial investment cost was 15.7% less. Ultimately, the use of direct drive versus a lithium-ion battery bank in an SDIS system for Dominican farms under 1 ha depends on the available capital resources of the farmer and whether they are able to put up sufficient initial capital or would rather pay less upfront and more over time. Noting that the sizing of the feasible SDIS configuration was conducted using historical weather data and climate change is expected to increase temperatures and change precipitation patterns in the future, a sensitivity analysis was conducted to gauge the impact of using historical data on the drawn conclusions. The analysis found that the decision as to what type of energy storage to use in an SDIS is not affected by accounting for climate change. However, using historical data to size an SDIS affected by climate change would likely result in an undersized system, given the predicted lifespan of 25 years of such a system. As such, additional research is needed to properly account for climate change effects in proper sizing techniques for SDIS systems for the Dominican Republic. Furthermore, future research should be focused on determining for larger Dominican farms whether multiple small-scale SDIS systems studied in this research or a large SDIS system should be implemented and whether such a system has a different techno-economical design. / När klimatförändringarna fortsätter att öka de globala temperaturerna och förändra nederbördsmönstren, har vattensystemen hamnat under ökat tryck, särskilt från jordbrukssektorn. Dessa klimateffekter på jordbrukssystem har visat sig vara mycket större för småskaliga producenter och små ö-nationer i utveckling. Som sådan är Dominikanska republiken, en karibisk ö-nation med en djup jordbrukskultur dominerad av småskaliga gårdar, särskilt sårbar. Som ett resultat har det funnits en global uppmaning att främja mer precisa och effektiva bevattningsmetoder, såsom droppbevattningssystem. Dock kräver dessa system oftast en extern energikälla. Eftersom energiproduktionen är en av de största bidragsgivarna till växthusgaser, bör förnybar energi användas för att verkligen ha ett hållbart bevattningssystem. Solkraftdrivna droppbevattningssystem (SDIS) har undersökts grundligt och visat sig vara tekniskt genomförbara och ekonomiskt lönsamma, men den tecno-ekonomiskt optimala konfigurationen är starkt beroende av sammanhanget där de tillämpas. Därför syftar denna avhandling till att undersöka och presentera en tecno-ekonomiskt optimal designmetod för SDIS för småskaliga dominikanska gårdar. För att göra detta genomfördes först en djupgående litteraturöversikt och marknadsanalys där det konstaterades att en fast PV-matris kopplad till en AC-driven variabel hastighetspump bör användas. Dessutom bör den exakta pumpen väljas från de lokalt tillgängliga som bäst matchar droppbevattningssystemets huvud- och flödesegenskaper. Dock pekade litteraturen inte på någon tydlig slutsats om ifall och vilken typ av energilagring som är bäst för SDIS. Därför, med hjälp av en fallstudie av en 1, 2 och 3 hektar stor platanodling vid Centro de Biotecnología Vegetal (CEBIVE) beläget i utkanten av Santo Domingo, fann man de minimistorlekar för möjliga konfigurationsalternativ för ett direktdrivet SDIS (utan lagring) tillsammans med ett batteripaket och en upphöjd vattentank. Dessa konfigurationer dimensionerades med hjälp av utvecklade algoritmer i Python som använde timvisa historiska väderdata från 2010 till 2023 och jämfördes enligt deras respektive nuvärdeskostnader (NPC) över 25 år och initiala investeringskostnader. Totalt sett fann man att för en gårdsplott på 2 och 3 hektar var ett direktdrivet system tecno-ekonomiskt optimalt. Samtidigt, för en gårdsplott på 1 hektar, även om det direktdrivna systemet minimerar SDIS-systemets NPC, fann man att den initiala investeringskostnaden var minimal för en av de möjliga batterikonfigurationerna (2 350W PV-paneler plus 1 kWh litiumjonbatterikapacitet). I detta fall var NPC för batterikonfigurationen 36,8% mer än det direktdrivna systemet, men den initiala investeringskostnaden var 15,7% mindre. I slutändan beror användningen av direktdrift jämfört med ett litiumjonbatteripaket i ett SDIS-system för dominikanska gårdar under 1 hektar på de tillgängliga kapitalresurserna hos jordbrukaren och om de kan ställa upp tillräckligt initialt kapital eller föredrar att betala mindre i början och mer över tid. Med tanke på att dimensioneringen av den genomförbara SDIS-konfigurationen genomfördes med hjälp av historiska väderdata och att klimatförändringar förväntas öka temperaturerna och förändra nederbördsmönstren i framtiden, genomfördes en känslighetsanalys för att bedöma effekten av att använda historiska data på de dragna slutsatserna. Denna analys visade att beslutet om ifall och vilken typ av energilagring som ska användas i ett SDIS inte påverkades, men att använda historiska data för att  dimensionera ett SDIS skulle troligen resultera i ett underdimensionerat system med tanke på livslängden på 25 år. Därför behövs ytterligare forskning för att korrekt ta hänsyn till klimatförändringseffekter i lämpliga dimensioneringstekniker för SDIS-system för Dominikanska republiken. Dessutom bör framtida forskning fokusera på att avgöra om för större dominikanska gårdar flera småskaliga SDIS-system som studerats i denna forskning eller ett stort SDIS-system bör implementeras och om ett sådant system har en annan tecno-ekonomisk design. / A medida que el cambio climático continúa aumentando las temperaturas globales y alterando los patrones de precipitación, los sistemas hídricos han estado bajo una mayor presión, especialmente desde el sector agrícola. Se ha encontrado que estos efectos climáticos en los sistemas agrícolas son mucho mayores para los pequeños productores y las naciones insulares en desarrollo. Por lo tanto, la República Dominicana, una nación insular del Caribe con una profunda cultura agrícola dominada por pequeñas fincas, es especialmente vulnerable. Como resultado, ha habido un llamado global para promover prácticas de riego más precisas y eficientes, como los sistemas de riego por goteo, sin embargo, estos sistemas a menudo requieren una fuente de energía externa. Siendo la producción de energía una de las mayores contribuyentes a los gases de efecto invernadero, se debe utilizar energía renovable para tener un sistema de riego verdaderamente sostenible. Los sistemas de riego por goteo alimentados por energía solar (SDIS) han sido ampliamente investigados y se ha encontrado que son técnicamente factibles y económicamente viables, sin embargo, la configuración óptima desde el punto de vista tecno-económico depende en gran medida del contexto en el que se aplican. Por lo tanto, esta tesis tiene como objetivo investigar y presentar una metodología de diseño tecno-económicamente óptima para SDIS en pequeñas fincas dominicanas. Para hacerlo, primero se realizó una revisión exhaustiva de la literatura y un análisis de mercado donde se encontró que se debería utilizar una matriz fotovoltaica fija acoplada con una bomba de velocidad variable alimentada por corriente alterna. Además, la bomba exacta debe ser elegida entre las disponibles localmente que mejor se adapten a las características de la cabeza y el caudal del sistema de riego por goteo. Sin embargo, la literatura no señaló una conclusión clara sobre sí y qué tipo de almacenamiento de energía es mejor para SDIS. Por lo tanto, utilizando el estudio de caso de una parcela de 1, 2 y 3 hectáreas de plátanos en el Centro de Biotecnología Vegetal (CEBIVE) ubicado en las afueras de Santo Domingo, se encontraron las opciones de configuración mínima viable para un SDIS de accionamiento directo (sin almacenamiento) junto con un banco de baterías y un tanque de agua elevado. Estas configuraciones fueron dimensionadas utilizando algoritmos desarrollados en Python que utilizaron datos meteorológicos históricos por hora desde 2010 hasta 2023 y se compararon según sus respectivos costos netos presentes (CNP) durante 25 años y los costos de inversión inicial. En general, se encontró que para una parcela de 2 y 3 hectáreas, un sistema de accionamiento directo era tecno-económicamente óptimo. Mientras tanto, para una parcela de 1 hectárea, aunque el sistema de accionamiento directo minimiza el CNP de los sistemas SDIS, se encontró que el costo de inversión inicial era mínimo para una de las configuraciones de batería viables (2 paneles fotovoltaicos de 350W más 1 kWh de capacidad de batería de iones de litio). En este caso, el CNP de la configuración de la batería era 36.8% más que el sistema de accionamiento directo, sin embargo, el costo de inversión inicial era 15.7% menos. En última instancia, el uso de un sistema de accionamiento directo frente a un banco de baterías de iones de litio en un sistema SDIS para fincas dominicanas de menos de 1 hectárea depende de los recursos de capital disponibles del agricultor y si pueden aportar suficiente capital inicial o prefieren pagar menos al principio y más con el tiempo. Teniendo en cuenta que el dimensionamiento de la configuración viable de SDIS se realizó utilizando datos meteorológicos históricos, y pronosticando que el cambio climático aumente las temperaturas y cambie los patrones de precipitación en el futuro, se realizó un análisis de sensibilidad para evaluar el impacto de utilizar datos históricos en las conclusiones obtenidas. Este análisis concluyó que la decisión sobre qué tipo de almacenamiento de energía utilizar en un SDIS no se ve afectada por el cambio climático. Sin embargo, el uso de datos históricos para dimensionar un SDIS afectado por el cambio climático probablemente daría lugar a un sistema subdimensionado, dada la vida útil prevista de 25 años de dicho sistema. Por lo tanto, es necesario seguir investigando para tener en cuenta los efectos del cambio climático en las técnicas de dimensionamiento de los sistemas SDIS en la República Dominicana. Además, la investigación futura debería centrarse en determinar, para las fincas dominicanas de mayor tamaño, si deberían implantarse múltiples sistemas SDIS a pequeña escala estudiados en esta investigación o un gran sistema SDIS, y si dicho sistema tiene un diseño tecno-económico diferente.

Il primo studio si focalizza sul diverso impatto di due categorie di strategie di Information Technologies coping sui livelli di ‘esaurimento lavorativo’ dei dipendenti (i.e, work exhaustion). Premesso un legame tra la percezione di due techno-stressors (techno-invasion e techno-overload) e l’accusare stress e problemi relativi all’equilibrio casa-lavoro (work-family conflict), si è proceduto tramite un sistema di equazioni strutturali e path analysis a valultare quanto significativamente diversi fossero i livelli di esaurimento lavorativo per i soggetti che utilizzassero strategie diverse per far fronte alle problematiche in esame. Il secondo studio sviluppa l’ipotesi di un effetto moderatore esercitato (sia singolarmente che in interazione reciproca) da bassi livelli di competizione tra gli impiegati ed alti livelli di ‘buona’ leadership sulla precezione del tecnostress sul lavoro. Si sono anche studiate le ricadute sul benessere dei dipendenti derivanti da un clima lavorativo percepito come altamente competitivo. Il terzo studio si propone di dimostrare statisticamente che il costrutto del distress (stress negativo) e quello dell’eustress (stress positivo) siano variabili profondamente diverse con i propri antecedenti e le conseguenze. Si dimostra quindi che non siano costrutti opposti o statisticamente ‘reciproci’. Il tutto è testato tramite tecniche di Structural Equation Modeling ed inquadrato all’interno del frame teorico del modello delle Job Demands – Resources. / This thesis will go through three empirical studies conducted in the past three years. The first study aims at deepening our understanding on how different technology-related stressors indirectly create negative outcomes. I specifically focus on work exhaustion as outcome because it has been demonstrated that it is a key detrimental state for employees’ wellbeing. Focusing on this outcome, I propose a model that explains how adaptive and maladaptive coping strategies influence it, and how they are indirectly informed by key technostress creators, namely techno-invasion and techno-overload. The second study will take in exam the action of two hypothetical technostress moderators: leadership climate and perceived competition on the job. Two distinct moderation effects techniques are tested using SPSS AMOS. The third study aims to statistically separate eustress construct (positive stress) from distress one (negative stress) since both concept are actually considered to be on the same continuum of the general stress measurement.

Les raves sont des événements festifs dédiés à la musique techno et à la danse qui se distinguent des autres lieux de rassemblement tels que les bars et les discothèques notamment par le fait qu’ils se déroulent toute la nuit dans un lieu aménagé pour l’occasion et qu’il n’y a généralement pas de vente d’alcool. La consommation de drogues de synthèse telles que l’ecstasy et les speeds y est toutefois largement répandue. La tenue de ces rassemblements pose une série de problèmes du point de vue des autorités policières, tels que la présence de trafiquants de drogues ainsi que la sécurité des lieux où se déroulent les raves. Dans le contexte particulier de ces événements, les pratiques de contrôle social sont soumises à un certain nombre d’ambiguïtés. Le but général de l’étude est de permettre une compréhension de la façon dont se déterminent et s’appliquent les règles qui visent à encadrer la tenue de ce type de rassemblements. Trois objectifs spécifiques sont poursuivis, soit 1) de comprendre comment on a tenté de réguler ce type d’événements à Montréal, 2) de comprendre comment les différents acteurs responsables de l’organisation et du bon déroulement des événements établissent une série de règles, aussi bien formelles qu’informelles, et négocient leur application dans le cadre de leur pratique, et 3) de comprendre comment ces acteurs identifient certaines situations comme constituant un problème et éventuellement, y réagissent. La principale méthode de recueil des données a consisté à réaliser des entretiens semi-dirigés avec des promoteurs d’événements rave, des agents de sécurité ainsi que d’autres personnes impliquées dans le milieu telles que policier, pompier, artistes de la scène rave et intervenants. L’observation participante lors d’événements rave fut utilisée comme méthode complémentaire. L’étude démontre comment le service de police s’est vu confronté avec les raves à un vide juridique et comment l’encadrement de ce type d’événements s’est plutôt exercé par le service de prévention des incendies. Les autorités ont également tenté d’encadrer le phénomène par des modifications à certaines règlementations, dont celles sur les permis d’alcool. L’étude démontre également de quelle manière et en fonction de quoi les différents acteurs du milieu négocient les règles en cours d’action dans un contexte où la frontière entre le licite et l’illicite est floue. / Raves are festive events dedicated to dance and techno music, different from other places of gathering such as bars and discotheques by the fact that they take place in all night venues converted for the occasion and where there is generally no sale of alcohol. Synthetic drug consumption such as ecstasy and speed is largely widespread in these events. The existence of these gatherings poses a series of problems from the point of view of the police authorities, such as the presence of drug dealers as well as the safety of the venue where the raves are held. In the particular context of these events, social control practices are subjected to a certain number of ambiguities. The general goal of this study is to allow an understanding of the way the rules, that constitute the framework of this type of gathering, are determined and applied. Three specific objectives pursued in this study are 1) to understand how authorities tried to control these types of events in Montreal, 2) to understand how the various actors responsible for the organization of these events establish a series of rules, formal and informal, and negotiate their application within the framework of their practice, and 3) to understand how these actors identify certain situations as problematic and eventually react to them. The main data collection method consisted in carrying out semi-directed interviews with rave Producers, Security Agents, Police Officer, Fire Marshal, Artists of the rave scene and other parties involved. Participating observation in actual events was a complementary method. This study demonstrates how the police service faced a legal void regarding rave events and how the regulatory framework was rather introduced by the fire department. The authorities also tried to control the rave phenomenon by modifying certain regulations, such as those applicable to alcohol licence. The study also demonstrates how and why key stakeholders negotiate the rules in the course of action in this particular context where the frontier between the licit and the illicit is woolly.